1. Field of the Invention
The present invention relates to a car security apparatus and a car security system for discouraging car theft and car tampering.
2. Description of the Related Art
Conventional car security apparatuses are typically provided with sensors for monitoring the opened or closed states of a car door, a bonnet and a trunk, and a sensor for detecting vibrations of the car. When any of these sensors detects an abnormal condition while the car security function of the apparatus is on (armed), a siren is sounded and an engine starter is disabled when an ignition switch is subsequently turned on.
The car security apparatus is typically operated from a remote control unit (hereinafter simply referred to as remote unit) that transmits cordless communication signals via radio waves, infrared rays, or ultrasonic waves. A user turns off (disarms) the security function of the apparatus while driving the car. When the user gets out of and leaves the car, he sends a signal from the remote unit to the car security apparatus to turn on (arm) the security function.
If one of the sensors fails and sends faulty (erroneous) detection signals in the conventional car security apparatus, the user may mistake the resulting alarm for a car tampering event because the user may not know that the sensor is faulty. To address this problem, some security apparatuses alert the user that a sensor is faulty by sounding a buzzer when the sensor fault is detected with the security function turned on. In this case, however, the user is still unable to isolate (locate) the faulty sensor because the buzzer is the same no matter which sensor becomes faulty.
In some conventional security apparatuses, a single remote unit may be used to control a plurality of car security apparatuses mounted in respective vehicles. In these units, the user must manually select a vehicle number on the remote unit corresponding to a selected one of the plurality of vehicles. If the user forgets the vehicle number of the selected vehicle, however, the user is required to repeatedly transmit signals to the cars while changing the selected vehicle number on the remote unit one by one until the car security apparatus in the intended vehicle operates. This is a tedious operation.
When any fault takes place in the conventional car security apparatus in a vehicle in which the security function is on (armed), the occurrence of the fault is evident from the resulting alarm (for example, the sounding a siren). The alarm is typically set such that it stops after a predetermined fixed time period. If the user does not hear the alarm before the fixed time period ends, the user may fail to notice that an abnormal condition has occurred, or the details regarding the abnormal condition (that is, which sensors were triggered at what time, for example).
In some car security apparatuses, the user is notified of a sensor that has detected an abnormal condition by a flashing pattern (time intervals between flashes) of an light-emitting diode. In this case, however, the user may have to consult a manual to identify which sensor was triggered by the abnormal condition from the flashing pattern of the LED, and such a step is inconvenient. In addition, this car security apparatus fails to notify the user of the time at which the sensor detected and thus was triggered by an abnormal condition.